We will use a version of the sample model "A) Airplan Ticket Reservation" for this article. After going to the Scenarios screen, here's what our table looks like.

On the Scenarios screen, click the "Freeze these Scenarios" button located in the top-right just above your first created test. 

You will be faced with the following warning message, reminding you that freezing your test cases should only be done when there is a valid reason to do so. If there is a valid reason to freeze the tests and you do wish to continue, click the "Freeze" button.

Once you click "Freeze," your existing test cases will be "frozen" as Forced Interactions. 

Here's what the Forced Interactions page looks like now. All of our tests have been "frozen" as the combinations of forced parameter values!

Let's add another parameter, "Amount of Luggage". At this point, we may have already run some of these scenarios, so we don't want to have to re-do any of them, even if Hexawise could reduce the total number. By freezing the previous 13 tests, Hexawise will keep them as they are, and simply add a couple scenarios to pair all of the new values - the numbers of luggage - with every other value. 

Here are the new tests. Note the initial 13 combinations are still present. We've simply added a few more.

Here's what the differences could have looked like if we had not frozen our initial 13 tests.

Notice how Test Case 3 contained the following while frozen:

Without freezing, the third row could contain the following after the new parameter was added and the table was "freshly" regenerated:

Therefore, we would have needed to re-run our initial scenarios. 

Important: Keep in mind that Freezing does not affect the functions built on top of values (e.g. value expansions, ranges). Those elements may show different choices when a frozen set of scenarios goes through regeneration. The more value expansions there are and/or the wider ranges are, the more likely you will see discrepancies.

Easy! We can do so by navigating to the Forced Interactions page and simply clicking the "Unfreeze" button above the table.